Implosive and preglottalized stops in Kiranti
The Kiranti languages are members of the Tibeto-Burman language family, the world’s largest language family in terms of speakers after Indo-European.
Among the Kiranti languages, the Western languages Bahing, Sunwar and Wambule are characterized by the presence of implosive or preglottalized stops in their modern phoneme inventories. These phonemes have not been attested in other Kiranti languages and are apparently unrelated to the preglottalized stops reconstructed for Proto-Eastern Kiranti, Proto-Thulung and Proto-Kiranti. The implosive or preglottalized stops /*ʔb-/ or /*ʔw-/ must therefore represent a Western Kiranti innovation.
Comparative evidence and internal reconstruction shows that Wambule occupies a special place among its closest relatives because the bilabial implosive /ɓ/ can be traced back not only to Western Kiranti /*ʔb-/ or /*ʔw-/, but also to Proto-Wambule /*ʔm-/, and because the main source for post-alveolar /ɗ/ is Proto-Wambule /*ʔn-/.